CN1312918C - Projection device and method for protecting the operation of the projector - Google Patents

Abstract

The invention provides a projection device and a projector operation protection method, which can prevent a CPU from losing control function due to high-voltage noise and electrostatic discharge interference generated by high starting voltage of a starting bulb and further can not deal with the problem of overhigh system temperature. A projection device, comprising: a power supply; a projection bulb; lightening the starter; an image processing system; a microprocessor; a plurality of cooling fans respectively arranged on at least one of the power supply, the projection lamp bulb and the image processing system; an interval charge-discharge loop; a reference voltage comparison circuit; a startup delay signal generating circuit; an AND gate; and a status latch and protection activation circuit. A projector operation protection method is generally used for a projector, and the projector comprises a microprocessor, a projection lamp bulb and a cooling fan which outputs a fan rotating speed signal corresponding to pulse frequency according to rotating speed.

Description

Projection device and method for protecting the operation of the projector

technical field

The invention relates to a projection device and a method for protecting the operation of the projector, in particular to a projection device and a method for protecting the operation of the projector which completely control and detect the rotation speed of the fan by hardware.

Background technique

When the traditional projection system is in operation, since the internal projection bulb and power supply are all heat-generating devices, in order to make the projector system operate stably, multiple sets of fans are needed to dissipate heat, so that the internal temperature of the projector system drops to the normal operating temperature to suit The projector system is working.

Most of the cooling fans inside the traditional projection system are controlled and activated by the microprocessor (CPU). The CPU uses thermal sensors to detect changes in the ambient temperature of the system, and determines the speed of the fan according to the temperature information detected and fed back by the thermal sensors to achieve heat dissipation and reduce fan noise.

However, since the projector must use a high voltage to start the projection lamp, the high voltage noise and electrostatic discharge generated by this high starting voltage can easily interfere with the CPU, causing it to "disorder" or "misoperation" and lose control. function, so it is unable to detect the ambient temperature and control the fan speed, so the system will be in a high temperature state at this time and cannot operate normally.

The method of the traditional technology to overcome the problem is to automatically reset (RESET) the microprocessor after the projector starts the projection lamp for a predetermined period of time (about two seconds) to solve the problem that it may be affected by the high voltage noise and electrostatic discharge caused by the high voltage of the startup. Interference that results in "confusion" or "malfunction". Furthermore, the traditional technology also adopts adding a thermal induction circuit breaker to temporarily interrupt the operation of the system according to the temperature of the system at the time.

However, the traditional solution only resets the CPU when the projector is turned on, but the projector system will be disturbed by noise at any time during operation, so the traditional solution cannot solve the noise problem that the projector system may encounter during operation. Even if there is no problem with the CPU, the disadvantage of using a thermal circuit breaker to detect the system temperature is that the error of the thermal circuit breaker is too large, which may cause the system to be too sensitive to temperature and often cut off the power.

Contents of the invention

In view of this, in order to solve the above-mentioned problems, the main purpose of the present invention is to provide a projection device and a method for protecting the operation of the projector, which can be used to control and detect the fan speed by an independent device that completely uses hardware to prevent problems caused by excessively slow fan speed. If the system temperature is too high, it does not need to be controlled by the software inside the CPU.

A projection device, comprising: a power supply;

A projection bulb for providing a projection light source;

a lighting starter for starting the projection bulb;

An image processing system for outputting projection images according to a video signal;

a microprocessor for controlling the image processor and providing the lighting start signal;

A plurality of cooling fans are respectively arranged on at least one of the power supply, the projection bulb, and the image processing system, to reduce the temperature at the location and output corresponding rotation speed signals according to their respective rotation speeds;

An interval charging and discharging circuit, which receives the speed signal of the fan and generates a continuous charging and discharging signal;

A reference voltage comparison circuit for comparing the voltage level of the continuous charging and discharging signal with a preset reference voltage level, and comparing the magnitudes of the two voltage levels to generate different voltage levels;

A power-on delay signal generating circuit, used to generate a signal after a specific delay time after power-on;

An AND gate, used to receive the voltage level output by the reference voltage comparison circuit and the signal of the start-up delay signal generation circuit, and output a corresponding voltage; and

A state latch and protection start circuit, used to receive the output voltage signal of the AND gate, when the output state of the AND gate changes, the circuit sends a protection start signal to the power supply, projection bulb, and image processing at least one of the systems.

In the projection device, the rotation speed signal is a pulse signal, and the frequency of the pulse signal is higher when the cooling fan rotates faster.

The projection device, wherein the image processing system includes:

An image processor, used for outputting image control signals according to externally input video signals;

A plurality of liquid crystal display panels display corresponding patterns according to the image control signal;

a projection lens for outputting the projected image according to the received signal; and

A plurality of reflectors are used to reflect the projection light emitted by the projection bulb and input to the projection lens through the liquid crystal display panel.

A method for protecting the operation of a projector, generally used for a projector, the projector includes a microprocessor, a projection bulb and a cooling fan that outputs a fan speed signal of a corresponding frequency according to the rotation speed, the method for protecting the operation of the projector includes Follow these steps:

receiving the fan speed signal, and generating a continuous charge and discharge signal; comparing the voltage level of the continuous charge and discharge signal with a preset reference voltage level, and correspondingly generating different voltage levels; comparing the Generate different voltage levels and a start-up delay signal, and output a corresponding voltage; and

The corresponding voltage is latched, and a protection start signal is sent to at least one of the power supply, projection lamp, and image processing system.

In the operation protection method of the projector, the rotation speed signal is a pulse signal, and the frequency of the pulse signal is higher when the cooling fan rotates faster.

The projection device and the projector operation protection method described in the present invention use hardware to control and detect the independent device of the fan speed to solve the situation that the system temperature is too high due to the fan speed being too slow, without the need for software inside the CPU. control, thus preventing the CPU from losing control functions due to high voltage noise and electrostatic discharge interference from the high starting voltage of the light bulb, and thus unable to deal with the problem of excessive system temperature.

Description of drawings

FIG. 1 shows a schematic structural view of a projection device according to a preferred embodiment of the present invention;

Fig. 2 shows the circuit diagram of the interval charging and discharging circuit according to a preferred embodiment of the present invention;

FIG. 3 shows a voltage sequence diagram of the pulse signal FAN FEEDBACK and the negative terminal of the comparator 326 in the fan pulse feedback modulation circuit 32;

FIG. 4A and FIG. 4B show timing diagrams of signals of the interval charge-discharge circuit according to a preferred embodiment of the present invention.

Explanation of reference symbols:

10 power supply

12 projection bulbs

13 thermal sensor circuit breaker

14 Light up the starter

16 image processing system

161 image processor

162 reflector

163 Filters

164 Projector Lens

18 microprocessor

19A, 19B, 19C cooling fans

20 Interval charging and discharging circuit

30 Power-on delay signal generation circuit

301 PNP transistor

303, 324 capacitors

305, 307 resistors

308 nodes

322 NPN transistor

326 comparators;

329 RC charging and discharging components

32 Fan pulse feedback modulation circuit

34 Status latch and protection start circuit

342 logic gates

344 D-type flip-flop

FAN FEEDBACK pulse signal

LCD liquid crystal display panel

R1, R2, R5 resistors

R3, R4 Voltage divider resistors

Vr Positive terminal voltage of the comparator

Vi Negative terminal voltage of the comparator

Vo Comparator output voltage

Detailed ways

Below are preferred specific embodiments of the present invention:

Referring to FIG. 1 , FIG. 1 is a schematic structural diagram showing a projection device according to an embodiment of the present invention. The projection device according to the embodiment of the present invention includes a power supply 10 for providing system power required for the operation of the projection device. The projection bulb 12 is used to provide a projection light source, and the projection bulb 12 is activated by a lighting starter 14 . The thermal induction breaker 13 of the conventional technology is arranged here. The image processing system 16 internally has an image processor 161 for outputting image control signals according to externally input video signals (including R, G, B data signals and horizontal and vertical scanning signals). A plurality of reflectors 162 are used to reflect the projection light source emitted by the projection bulb 12 to the liquid crystal display panel LCD, and the liquid crystal display panel LCD displays corresponding patterns according to the image control signal, so that the light passes through the liquid crystal display panel and passes through the filter. After the light is filtered by the mirror 163 , the projected image is output from the projector lens 164 . The microprocessor 18 is used to control the image processor 161 and provide a lighting start signal for enabling the lighting actuator 14 . In addition, a plurality of cooling fans 19A- 19C are respectively installed in the power supply 10 , the projection bulb 12 , and the image processing system 16 to reduce the temperature of the installed locations and output corresponding rotation speed signals according to their respective rotation speeds. Here, whenever the cooling fan rotates once, two pulse signals with the same width will be generated. When the fan speed is faster, the pulse frequency of the output speed signal FAN FEEDBACK is higher, on the contrary, when the fan speed is slower, the pulse frequency of the output speed signal is lower. In this way, the interval charging and discharging circuit 20 can know the fan speed according to the pulse frequency of the speed signal, and output a judgment signal representing whether the fan speed is normal or abnormal. The judgment signal representing abnormal fan speed is respectively input to the microprocessor 18, the power supply 10 and the projection lamp 12, etc., for resetting the microprocessor 18, controlling the power supply 10 to turn off the system power, and turning off the projection lamp 12 etc.

FIG. 2 is a circuit diagram showing an interval charging and discharging circuit according to an embodiment of the present invention. As shown in FIG. 2 , the interval charge-discharge circuit according to the embodiment of the present invention includes a power-on delay signal generation circuit 30 , a fan pulse feedback modulation circuit 32 , and a state latch and protection start-up circuit 34 .

The power-on delay signal generating circuit 30 is composed of a PNP transistor 301 and a plurality of resistors and capacitors; the emitter terminal of the transistor 301 is connected with a resistor, and the other terminal of the resistor is connected with a Vcc voltage source and a ground respectively. capacitor; the base terminal of the transistor 301 is electrically connected with the LAMP STATUS signal output terminal of the lighting starter 14; the collector terminal of the transistor 301 is electrically connected with one end of the resistor 305 and the capacitor 303 respectively, and the other end of the capacitor 303 It is electrically connected to one end of the resistor 307, and the other end of the resistor 305 and the resistor 307 is grounded; the output terminal 308 of the power-on delay signal generating circuit 30 is grounded through a resistor R5.

The fan pulse feedback modulation circuit 32 is composed of an NPN transistor 322, a comparator 326, an RC charging and discharging assembly 329, and a plurality of resistors and capacitors; the base terminal 327 of the NPN transistor 322 is connected to the pulse signal output by the fan. FAN FEEDBACK is electrically connected, the collector terminal of the NPN transistor 322 is electrically connected to a Vcc voltage source through a resistor, and the emitter terminal of the NPN transistor 322 is electrically connected to the RC charging and discharging component 329, that is, the emitter terminal is connected to the resistors R1 and R2 respectively One end of the resistor R2 is electrically connected to one end of a capacitor, and the capacitor and the other end of the resistor R1 are connected to the ground, and the electrical connection end 328 of the resistor R2 and the capacitor is connected to the negative electrode of the comparator 326. Terminals are electrically connected; the positive terminal of the comparator 326 is electrically connected to one end of the voltage dividing resistor R3, R4, and the other end of the resistor R3 is electrically connected to the Vcc voltage source, and the other end of the resistor R4 is grounded. The output terminal of the comparator 326 is connected with a grounding resistor in parallel, wherein, for convenience of explanation, the positive terminal voltage of the comparator 326 is Vr, and the negative terminal voltage of the comparator 326 is Vi, and the output terminal of the comparator 326 The voltage is Vo.

This state latch and protection starting circuit 34 is to be provided with an AND gate 342, a D-type flip-flop 344 and a plurality of resistances and electric capacity to form; Vo is electrically connected, and the other input end of the AND gate 342 is electrically connected with the output end 308 of the start-up delay signal generating circuit 30; the output end of the AND gate 342 is electrically connected with a Vcc voltage source through a resistance, and the Vcc The voltage source is connected to a ground capacitor, and the output terminal of the AND gate 342 is electrically connected to the CLK terminal of the D-type flip-flop; the D-terminal of the D-type flip-flop 344 is grounded, and the reset input terminal PR is connected to the system to start The signal output terminal is electrically connected, and when the system starts up normally, the system start-up signal RSTn received by the reset input terminal PR is at a high level. In addition, the CL terminal of the D-type flip-flop is electrically connected to a ground capacitor and a 5V voltage respectively.

When the microprocessor detects that the power button is activated, it starts to execute the system self-test program, including peripheral components, fan status, and ambient temperature. The start signal is sent to the reset input PR of the D-type flip-flop 344 . When the projection lamp is successfully lit, the lighting starter will automatically reply the "LAMP STATUS" signal, the logic is "0", if it is not successful, it will be "1". When the projection lamp is successfully lit, then use the "LAMP STATUS" signal The delay circuit 30 is driven, and the interval charging and discharging circuit is not started until the system is stable.

When the projector system is just started, it will be in an unstable state for a period of time, so the start-up delay signal generation circuit 30 is needed to make a proper delay, and then start the interval charging and discharging circuit after the system is stable to avoid generating wrong detection information. Referring to block 30 of the start-up delay signal generating circuit in FIG. 2, when the logic level of the "LAMP STATUS" signal is switched to "0", it means that the projection bulb is successfully lit, so the PNP transistor 301 is turned on, and the timing resistor 305 is turned on. The potential rises immediately, and the node 308 increases the voltage due to the coupling effect of the capacitor 303, but after a period of delay, the voltage level of the node 308 gradually drops to a low level, and through the conversion of the inverter 309, a high output is output level signal to AND gate 342. Here, the delay time can be set by adjusting the capacitance of the capacitor 303 and the resistance of the resistors 305 and 307 .

Referring to block 32 of the fan pulse feedback modulation circuit in FIG. 2, the "FAN FEEDBACK" signal is a pulse signal output by the fan. When the "FAN FEEDBACK" signal is at a high level, the NPN transistor is turned on, thus starting to charge the capacitor 324 , when the "FAN FEEDBACK" signal returns to low level, then stop charging. As a result of repeated charging, a predetermined level will be formed at the negative terminal of the comparator 326, as shown in FIG. 3 . At this time, a reference voltage Vr is provided at the positive terminal of the comparator 326 for comparison with the voltage level Vi at the negative terminal. Depending on the voltage value generated by the negative terminal, it can be adjusted by a variable resistor. Therefore, when the fan speed is normal, the voltage value Vi received by the negative terminal of the comparator 326 is greater than the reference voltage Vr received by the positive terminal, so the output terminal of the comparator 306 outputs a low level signal. When the fan speed is too low, the voltage value Vi received by the negative terminal of the comparator 326 will be smaller than the reference voltage Vr received by the positive terminal, so the output terminal of the comparator 306 outputs a high level signal, indicating that the fan speed is abnormal at this time.

Referring to block 34 of the state latch and protection startup loop in FIG. 2 , when the fan speed is normal, the AND gate 342 outputs a logic level of “0” to the CLK terminal of the D-type flip-flop 344 . FIG. 4A shows a signal sequence diagram of the fan pulse feedback modulation circuit 32 and the state latch and protection startup circuit 34 when the fan speed is normal. Taking the fan speed reference voltage Vr as 1.8V as an example, when the fan speed cycle (duty cycle) is 40ms and the voltage Vi received by the negative terminal of the comparator 326 is 1.9V, the fan speed is 750 R.P.M. Since the voltage value Vi received by the negative terminal of the comparator 326 is greater than the reference voltage Vr received by the positive terminal, the comparator 326 outputs a "0" logic level to the input terminal of the AND gate 342, so the AND gate 342 outputs "0". ” logic level to the CLK terminal of the D-type flip-flop 344. At this time, the Q terminal of the D-type flip-flop 344 outputs a "1" logic level.

FIG. 4B is a signal sequence diagram showing the fan pulse feedback modulation circuit 32 and the state latch and protection startup circuit 34 when the fan speed is too low. When the duty cycle of the fan is 100 ms, the voltage value Vi received by the negative terminal of the comparator 326 is about 1.58 V, and the fan speed is 300 R.P.M. As shown in FIG. 4B, since the voltage value Vi received by the negative terminal of the comparator 326 begins to be lower than the reference voltage Vr received by the positive terminal, the comparator 326 continuously outputs pulses of “1” logic level to the gate of the AND gate 342. At the input end, because the system has passed the delay time at this time, the start-up delay signal generating circuit 30 also outputs a high-level signal to the AND gate 342, so the AND gate 342 outputs a "1" logic level to the CLK terminal of the D-type flip-flop 344 . The power-on delay signal generation circuit triggers the D-type flip-flop 344 to lock the logic signal output by the AND gate 342, and simultaneously the Q terminal of the D-type flip-flop 344 will change from "1" to "0", when the D-type flip-flop 344 When the Q terminal outputs a low-level signal, it means that the fan speed has been detected to be too low at this time, so corresponding system protection actions must be performed, such as resetting the microprocessor 18, controlling the power supply 10 to turn off the system power, and Turn off the projection lamp 12, etc.

To sum up, according to the projection device and the projector operation protection method disclosed in the embodiments of the present invention, an independent device that completely controls and detects the fan speed by hardware can solve the problem of overheating of the system caused by the fan speed being too slow. The situation does not need to be controlled by the software inside the CPU, so it can prevent the CPU from losing its control function due to the high-voltage noise and electrostatic discharge interference generated by the high starting voltage of the light bulb, and thus cannot deal with the problem of excessive system temperature. Furthermore, according to the circuit for judging the fan speed disclosed in the embodiment of the present invention, its simple circuit design has the advantages of high stability and fast speed, which greatly improves the disadvantages of traditionally using a thermal sensor circuit breaker to detect system temperature.

Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the scope of the present invention. Any person familiar with the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, this The scope of protection of an invention shall be defined by the patent scope of the claims.

Claims (5)

1, a kind of projection arrangement is characterized in that comprising:

One power supply unit;

One projection bulb is in order to provide projection light source;

One lights starter, starts described projection bulb in order to light enabling signal according to one;

One image processing system is in order to export projected image according to a vision signal;

One microprocessor is in order to control described image processor and the described enabling signal of lighting is provided;

A plurality of radiator fans, be arranged at respectively described power supply unit, projection bulb and image processing system one of at least, export corresponding tach signal in order to the temperature that reduces the placement and according to separately rotating speed;

One rotation speed of the fan testing circuit receives the tach signal of these radiator fans, and produces one and discharge and recharge signal continuously;

One reference voltage comparison circuit for relatively this discharges and recharges a voltage of signals level and a default reference voltage level continuously, and compares the size of two voltage levels, produces different voltage levels;

One start inhibit signal produces circuit, in order to light enabling signal and is producing the inhibit signal of starting shooting after the time through a specific delays after the start according to above-mentioned;

One with door, in order to the voltage level that receives the output of this reference voltage comparison circuit and the signal of this start inhibit signal generation circuit, and export a corresponding voltage; And

One state bolt-lock and protection start the loop; in order to receive this with the door output voltage signal; when this output state with door changes; the enabling signal that a protection is promptly sent in this loop to this power supply unit, projection bulb and image microprocessor one of at least, to carry out at least one step of resetting above-mentioned microprocessor, closing above-mentioned power supply unit and close above-mentioned projection bulb.

2, projection arrangement as claimed in claim 1 is characterized in that: described tach signal is a pulse signal, and when described radiating fan rotation speed was fast more, then the frequency of described pulse signal was high more.

3, projection arrangement as claimed in claim 1 is characterized in that described image processing system comprises:

One image processor, the output image control signal in order to the vision signal of importing according to the outside;

A plurality of display panels show corresponding pattern according to described image control signal;

One projection camera lens is in order to export described projected image according to the signal that is received; And

A plurality of speculums in order to reflect the projection light source that described projection bulb sends, are input to described projection camera lens via described display panels.

4, a kind of projector running protection method; be applicable to a projector; described projector comprises a microprocessor, and a projection bulb and export the radiator fan of the fan rotating speed signals of respective frequencies according to rotating speed is characterized in that described projector running protection method comprises the following steps:

Above-mentioned projector is producing a start inhibit signal through a specific delays after the start after the time;

Receive described fan rotating speed signals, and produce one and discharge and recharge signal continuously;

The more described size that discharges and recharges a voltage of signals level and a reference voltage level of presetting continuously, and the different voltage level of corresponding generation;

According to described different voltage levels and the start inhibit signal of producing, export a corresponding voltage; And

When above-mentioned corresponding voltage status changes; the enabling signal of sending protection to described power supply unit, projection bulb and image microprocessor one of at least, to carry out at least one step of resetting above-mentioned microprocessor, closing above-mentioned power supply unit and close above-mentioned projection bulb.

5, projector as claimed in claim 4 running protection method, it is characterized in that: described tach signal is a pulse signal, when described radiating fan rotation speed was fast more, then the frequency of described pulse signal was high more.

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